>> he needed $8,200 and 9, $9,800, and $9,700. >> so katherine, how much money total did you loan budimir? >> i believe around $400,000. >> you loaned him your entire life savings? >> i loaned him everything. >> reporter: and despite the endless borrowing, katherine stays in the relationship. a combination of misguided trust and a very real fear. >> once katherine underwood had invested $100,000, $200,000, she began to believe that the only way she could even get her money back is if the project became a success. >> it stretched out year after year? >> yeah, i felt trapped. the more i gave him, the more scared i was. >> of losing all your money? >> yeah. >> reporter: when we return, underwood undercover. katherine attempts to follow the man, and the money. the master of disguise gets close to budimir. real close.